From 396f412f8711cee964bf0a3c2587cdf1ed373313 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Tue, 16 Jun 2026 12:22:04 +0200
Subject: [PATCH] Fix spline editing in large worlds

#4132
---
 Source/Engine/Debug/DebugDraw.cpp     | 16 +++++++++++-----
 Source/Engine/Debug/DebugDraw.h       |  6 ++++--
 Source/Engine/Level/Actors/Spline.cpp |  8 +++++---
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/Source/Engine/Debug/DebugDraw.cpp b/Source/Engine/Debug/DebugDraw.cpp
index 18552dcec..0e1768f63 100644
--- a/Source/Engine/Debug/DebugDraw.cpp
+++ b/Source/Engine/Debug/DebugDraw.cpp
@@ -357,7 +357,7 @@ struct DebugDrawContext
     Vector3 Origin = Vector3::Zero;
     DebugDrawData DebugDrawDefault;
     DebugDrawData DebugDrawDepthTest;
-    Float3 LastViewPos = Float3::Zero;
+    Vector3 LastViewPosition = Vector3::Zero;
     Matrix LastViewProjection = Matrix::Identity;
     BoundingFrustum LastViewFrustum;
 
@@ -790,9 +790,14 @@ bool DebugDraw::CanClear(void* context)
 
 #endif
 
-Vector3 DebugDraw::GetViewPos()
+Vector3 DebugDraw::GetViewPosition()
 {
-    return Context->LastViewPos;
+    return Context->LastViewPosition;
+}
+
+Vector3 DebugDraw::GetViewOrigin()
+{
+    return Context->Origin;
 }
 
 BoundingFrustum DebugDraw::GetViewFrustum()
@@ -802,7 +807,7 @@ BoundingFrustum DebugDraw::GetViewFrustum()
 
 void DebugDraw::SetView(const RenderView& view)
 {
-    Context->LastViewPos = view.Position;
+    Context->LastViewPosition = view.WorldPosition;
     Context->LastViewProjection = view.Projection;
     Context->LastViewFrustum = view.Frustum;
 }
@@ -1420,7 +1425,8 @@ void DebugDraw::DrawWireSphere(const BoundingSphere& sphere, const Color& color,
     int32 index;
     const Float3 centerF = sphere.Center - Context->Origin;
     const float radiusF = (float)sphere.Radius;
-    const float screenRadiusSquared = RenderTools::ComputeBoundsScreenRadiusSquared(centerF, radiusF, Context->LastViewPos, Context->LastViewProjection);
+    const Float3 drawPos = Context->LastViewPosition - Context->Origin;
+    const float screenRadiusSquared = RenderTools::ComputeBoundsScreenRadiusSquared(centerF, radiusF, drawPos, Context->LastViewProjection);
     if (screenRadiusSquared > DEBUG_DRAW_SPHERE_LOD0_SCREEN_SIZE * DEBUG_DRAW_SPHERE_LOD0_SCREEN_SIZE * 0.25f)
         index = 0;
     else if (screenRadiusSquared > DEBUG_DRAW_SPHERE_LOD1_SCREEN_SIZE * DEBUG_DRAW_SPHERE_LOD1_SCREEN_SIZE * 0.25f)
diff --git a/Source/Engine/Debug/DebugDraw.h b/Source/Engine/Debug/DebugDraw.h
index 8e2713ac5..c4ae12283 100644
--- a/Source/Engine/Debug/DebugDraw.h
+++ b/Source/Engine/Debug/DebugDraw.h
@@ -74,8 +74,10 @@ API_CLASS(Static) class FLAXENGINE_API DebugDraw
     API_FUNCTION() static bool CanClear(void* context = nullptr);
 #endif
 
-    // Gets the last view position when rendering the current context. Can be used for custom culling or LODing when drawing more complex shapes.
-    static Vector3 GetViewPos();
+    // Gets the last view position (world-space) when rendering the current context. Can be used for custom culling or LODing when drawing more complex shapes.
+    static Vector3 GetViewPosition();
+    // Gets the last view origin (world-space) when rendering the current context. Can be used for custom culling or LODing when drawing more complex shapes.
+    static Vector3 GetViewOrigin();
     // Gets the last view frustum when rendering the current context. Can be used for custom culling or LODing when drawing more complex shapes.
     static BoundingFrustum GetViewFrustum();
 
diff --git a/Source/Engine/Level/Actors/Spline.cpp b/Source/Engine/Level/Actors/Spline.cpp
index 271609396..9837835c1 100644
--- a/Source/Engine/Level/Actors/Spline.cpp
+++ b/Source/Engine/Level/Actors/Spline.cpp
@@ -496,7 +496,7 @@ namespace
     FORCE_INLINE float NodeSizeByDistance(const Vector3& nodePosition, bool scaleByDistance)
     {
         if (scaleByDistance)
-            return (float)(Vector3::Distance(DebugDraw::GetViewPos(), nodePosition) / 100);
+            return (float)(Vector3::Distance(DebugDraw::GetViewPosition(), nodePosition) / 100);
         return 5.0f;
     }
 
@@ -507,7 +507,7 @@ namespace
             return;
         Spline::Keyframe* prev = spline->Curve.GetKeyframes().Get();
         Vector3 prevPos = transform.LocalToWorld(prev->Value.Translation);
-        Real distance = Vector3::Distance(prevPos, DebugDraw::GetViewPos());
+        Real distance = Vector3::Distance(prevPos, DebugDraw::GetViewPosition());
         if (distance < METERS_TO_UNITS(800)) // 800m
         {
             // Bezier curve
@@ -540,7 +540,9 @@ namespace
 
 void Spline::OnDebugDraw()
 {
-    if (DebugDraw::GetViewFrustum().Intersects(_sphere))
+    BoundingSphere sphere(_sphere);
+    sphere.Center -= DebugDraw::GetViewOrigin();
+    if (DebugDraw::GetViewFrustum().Intersects(sphere))
         DrawSpline(this, GetSplineColor().AlphaMultiplied(0.7f), _transform, true);
 
     // Base